Uzi Motro - Profile on Academia.edu (original) (raw)
Papers by Uzi Motro
Theoretical and Applied Genetics, Feb 1, 1993
As compared to classical, fixed sample size techniques, simulation studies showed that a proposed... more As compared to classical, fixed sample size techniques, simulation studies showed that a proposed sequential sampling procedure can provide a substantial decrease (up to 50~, in some cases) in the mean sample size required for the detection of linkage between marker loci and quantitative trait loci. Sequential sampling with truncation set at the required sample size for the non-sequential test, produced a modest further decrease in mean sample size, accompanied by a modest increase in error probabilities. Sequential sampling with observations taken in groups produced a noticeable increase in mean sample size, with a considerable decrease in error probabilities, as compared to straightforward sequential sampling. It is concluded that sequential sampling has a particularly useful application to experiments aimed at investigating the genetics of differences between lines or strains that differ in some single outstanding trait.
Natural mortality of the tobacco whitefly (Bemisia tabaci) in Israel cotton fields
Selfish cooperation in social roles: the vigilance game in continuous time
Springer eBooks, 1990
Social interactions in nature often involve conflict to a certain extent. Game theory can sometim... more Social interactions in nature often involve conflict to a certain extent. Game theory can sometimes provide us with insight and tools to improve our understanding of how natural selection has resolved such conflicts. Undoubtedly, the major conceptual tool in this field is the concept of evolutionarily stable strategies (ESS), which was introduced by Maynard Smith and Price (1973). A strategy, in an evolutionary context, is one of a set of possible alternative behavioural programmes that an individual in a population can adopt. It is usually assumed that these are genetically determined. An ESS is a strategy which, when adopted by a large enough fraction of the population, cannot be invaded by any alternative rare (‘mutant’) strategy. A rare ESS strategy can invade a non-ESS population.
Journal of Forensic Sciences, Jul 1, 1999
This case report demonstrates a rape case, where no semen, hair, or fingerprints were left by the... more This case report demonstrates a rape case, where no semen, hair, or fingerprints were left by the perpetrator at the crime scene, but rather uncharacteristic biological and physical evidence in the form of a lollipop and a pair of glasses. Three separate forensic laboratories collaborated using conventional forensic methods of PCR DNA typing, photography, and toolmark comparisons to provide investigators with scientific evidence which in turn was instrumental in bringing a violent criminal to justice. The importance of evaluating each item of evidence and realizing its forensic value is stressed in this case report.
Effect of supplemental feeding on nesting success in the Lesser Kestrel (Falco naumanni)
RePEc: Research Papers in Economics, 2018
<jats:p>The effect of food supplement to Lesser Kestrel (<jats:italic>Falco naumanni&... more <jats:p>The effect of food supplement to Lesser Kestrel (<jats:italic>Falco naumanni</jats:italic>) nests during the nestling period (from hatching to fledging) was studied in two nesting colonies in Israel – Alona and Jerusalem. Our hypothesis, based on diminishing returns considerations, was that food supplement will have a greater effect on fledgling success in the food-limited, urban colony of Jerusalem, than in the rural colony of Alona. Indeed, food supplement had a significantly positive effect on breeding success in both colonies. However, and contrary to our prediction, the decrease in chick mortality between supplemented and control nests in Jerusalem was not larger than in Alona (actually it was numerically smaller, albeit not significantly so). This implies either that additional factors, possibly urbanization associated, other than food limitation, might be responsible for the difference in nesting success of Lesser Kestrels between Alona and Jerusalem, and/or that the amount or the nutritional quality of the additional food provided to supplemented nests (three mice per chick per week), was not enough.</jats:p>
The Three Brothers' Problem: Kin Selection
The theory of kin selection was introduced by Hamilton (1963, 1964) and developed further by many... more The theory of kin selection was introduced by Hamilton (1963, 1964) and developed further by many others in terms of help directed from one relative (the donor) toward another (the recipient). In this paper, as well as its companion (Eshel and Motro 1988), we deal with the more complex (though quite common) situation in which an individual needs help, and this help can be provided (with some risk to the donor) by each of several relatives. In such a situation, even if Hamilton's condition for altruism between two relatives is satisfied, it is advantageous to stand by and wait for another relative to take the risk and help the relative in need. It is true, though, that if all helpers are passive, Hamilton's argument again holds, and any potential helper can increase its own inclusive fitness by exclusively taking the risk and saving the relative in need. However, this entails an even greater increase in the inclusive fitness of the other relatives that decided not to offer their help. The analysis of situations involving more than one potential helper carried out in the preceding paper (Eshel and Motro 1988) and in this paper reveals that if Hamilton's condition for one-to-one altruism does not hold, full selfishness is the only evolutionarily stable strategy (ESS) independent of the number of helpers. If, however, Hamilton's condition is satisfied, the ESS in the multiple-help cases is usually a mixed strategy of altruism and selfishness, characterized by a positive probability of providing the needed help. In the preceding paper we analyzed situations in which immediate help is needed. In such cases, each potential helper has to decide instantaneously whether or not to offer its help, without knowing what the other potential helpers are doing. Here we discuss the case of delayed help. Each potential helper can wait in the hope that another relative will take the risk and help the individual in need; yet if they all hesitate too long, it might be too late for the relative in distress. We first present an ESS model of delayed help, based on arguments of the maximization of inclusive fitness. We then add a simple genetic model, whose results coincide (at least for the case studied) with those obtained by the ESS
Journal of Theoretical Biology, Jun 1, 2004
The parental investment conflict considers the question of how much each sex should invest in eac... more The parental investment conflict considers the question of how much each sex should invest in each brood, thereby characterizing different animal groups. Each such group usually adopts a certain parental care pattern: female-care only, male-care only, biparental care, or even no parental care at all. The differences in care patterns are usually explained by the different costs and benefits arising from caring for the offspring in each animal group. This paper proposes a game-theoretical model to the parental investment conflict based on the parental behavior in Cichlid fish. Cichlid fish exhibit different parental care patterns, allowing the examination of the factors which determine the particular behavior in each mating. We present a continuous time, two-stage, asymmetric game, with two types of players: male and female. According to the model's results, three parental care patterns: male-only care, female-only care and biparental care, are possible Evolutionarily Stable Strategies. Fixation depends on the investment costs and benefits, and on the initial conditions of the game. These results may explain the different parental care patterns observed in different animal groups as well as in Cichlid fish.
bioRxiv (Cold Spring Harbor Laboratory), May 25, 2020
The circadian and endocrine systems influence many physiological processes in animals, but little... more The circadian and endocrine systems influence many physiological processes in animals, but little is known on the ways they interact in insects. We tested the hypothesis that juvenile hormone (JH) influences circadian rhythms in the social bumble bee Bombus terrestris. JH is the major gonadotropin in this species coordinating processes such as vitellogenesis, oogenesis, wax production, and behaviors associated with reproduction. It is unknown however, whether it also influences circadian processes. We topically treated newly-emerged bees with the allatoxin Precocene-I (P-I) to reduce circulating JH titers and applied the natural JH (JH-III) for replacement therapy. We repeated this experiment in three trials, each with bees from different source colonies. Measurements of ovarian activity suggest that our JH manipulations were effective; bees treated with P-I had inactive ovaries, and this effect was fully recovered by subsequent JH treatment. We found that JH augments the strength of circadian rhythms and the pace of rhythm development in individually isolated newly emerged worker bees. JH manipulation did not affect the free-running circadian period, overall level of locomotor activity, sleep amount, or sleep structure. Given that acute manipulation at an early age produced relatively long-lasting effects, we propose that JH effects on circadian rhythms are mostly organizational, accelerating the development or integration of the circadian system.
Nest-site fidelity in Lesser Kestrels: a case of Win–Stay/Lose–Shift?
Israel Journal of Ecology & Evolution, Nov 6, 2019
We studied Lesser Kestrels’ (Falco naumanni) conditional nest-site fidelity, i.e., fidelity that ... more We studied Lesser Kestrels’ (Falco naumanni) conditional nest-site fidelity, i.e., fidelity that depends on the outcome of the previous nesting attempt in that site. In particular, we were interested in examining whether individual kestrels practice a Win–Stay/Lose–Shift (WSLS) strategy towards their nest-sites; that is, does the tendency to use the same nest-site increase following a successful nesting season, but decrease following a failure. For that purpose, we documented the use of nest-sites by Lesser Kestrels and the breeding success in these sites during 1998–2003 in the city of Jerusalem (Israel). We found that while Lesser Kestrels do not practice WSLS strategy towards their nest-site, the males (but not the females) do so towards their sub-colony – they tend to stay in the same sub-colony if their nesting was successful, whereas they tend to migrate to a different sub-colony after failure. A possible explanation to this sexual difference in WSLS behavior can arise from the fact that changing a sub-colony entails a change of hunting area. The male, being the main food provider in the Lesser Kestrel, may be more sensitive to this opportunity.
Molecular analysis separates the Atlantic population of Montagu's stellate barnacle into two cryptic species
Zoologica Scripta
Brewed in the African pot: the phylogeography of the toothed barnacle Chthamalus dentatus (Chthamaloidea: Chthamalidae)
Marine Biology Research
Insects
During recent decades, bumble bees (Bombus terrestris) have continuously expanded their range in ... more During recent decades, bumble bees (Bombus terrestris) have continuously expanded their range in the Mediterranean climate regions of Israel. To assess their potential effects on local bee communities, we monitored their diurnal and seasonal activity patterns, as well as those of native bee species in the Judean Hills. We found that all bee species tend to visit pollen-providing flowers at earlier times compared to nectar-providing flowers. Bumble bees and honey bees start foraging at earlier times and colder temperatures compared to other species of bees. This means that the two species of commercially managed social bees are potentially depleting much of the pollen, which is typically non-replenished, before most local species arrive to gather it. Taking into consideration the long activity season of bumble bees in the Judean hills, their ability to forage at the low temperatures of the early morning, and their capacity to collect pollen at early hours in the dry Mediterranean cli...
The impact of Acacia saligna and the loss of mobile dunes on rodent populations: a case study in the Ashdod-Nizzanim sands in Israel
Israel Journal of Plant Sciences, 2019
The Mediterranean coastal dune habitat of Israel is diminishing rapidly, mostly due to massive ur... more The Mediterranean coastal dune habitat of Israel is diminishing rapidly, mostly due to massive urbanization, changes in habitat characteristics caused by dune stabilization and the presence of Acacia saligna, an invasive species brought to Israel for the purpose of dune stabilization. In this study we document the effect of sand stabilization on the composition of small mammal communities in the Ashdod-Nizzanim sands, Israel. We analyzed differences in species diversity and abundance for species of rodents in four types of habitat: unstable (mobile) sand dune, semi-stabilized dune, inter-dune depression and a plot of the invasive Acacia saligna. Rodent communities were found to undergo gradual changes concurrently with the stabilization of the sands. The mobile dune was the only habitat in which the strict psammophiles Jaculus jaculus and Gerbillus pyramidum were captured in abundance. No species commensal with human were captured neither in the mobile nor in the semi-stabilized dun...
Mammal Research, 2019
A trapping study was conducted to compare the efficacy of 11 different small mammal traps-seven l... more A trapping study was conducted to compare the efficacy of 11 different small mammal traps-seven live-traps and four lethaltraps-in capturing pest rodents in agricultural fields and orchards. The 9-year study was carried out in various regions in Israel, and comprised of 648 trap-sets, totalling over 32,000 trap-nights. Mice comprised the great majority (over 85%) of captures, with Tristram's jirds in the second place (about 8%). Among the traps, the Victor Mouse snap-trap displayed the greatest capturing rate (10.05%), followed by the Sherman live-trap (8.88%) and the Ugglan live-trap (6.28%). Pairwise comparisons were performed only between the four most abundant traps-Victor Mouse, Box, Victor Rat, and Sherman. For mice, the most attractive trap was the Victor Mouse, second in attractiveness was the Sherman, third was the Box live-trap, and the least of the four was the Victor Rat snap-trap. For the larger jirds, the attractiveness hierarchy was reversed, with Victor Mouse being the least attractive. These results shed light on rodent traps and rodent trappability in various agricultural environments and with regard to target species. A careful choice of trap types should be exercised to best address mission goals.
Israel Journal of Ecology and Evolution, 2017
We studied the use of nest-sites by Griffon Vultures (Gyps fulvus) and the breeding success in th... more We studied the use of nest-sites by Griffon Vultures (Gyps fulvus) and the breeding success in these sites during 1998–2002 in Gamla Nature Reserve (Israel). Nest-sites in which a breeding attempt succeeded in fledging a young, were more likely to be occupied by nesting vultures in the following breeding season, than nest-sites that experienced a failure. This suggests that Griffon Vultures in Gamla used a Win–Stay/Lose–Shift strategy regarding nest-site fidelity.
Animal Conservation, 2018
Increased fragmentation and easier access to natural areas (e.g. ecotourism) is bringing man in c... more Increased fragmentation and easier access to natural areas (e.g. ecotourism) is bringing man in closer contact to wild populations. Such encounters, even when they don't pose a direct threat to wildlife, may induce behavioral changes in animals that in the long run may have negative fitness consequences. We studied changes to the vigilance/group‐size effect in Nubian ibex Capra nubiana in response to increased non‐threatening anthropogenic disturbance in six sites, subject to different levels of ecotourism. In each site we regressed the average time ibex individuals devoted to vigilance on the size of the group they were with. We then compared the slopes and intercepts of the vigilance/group‐size function between the six sites. We complimented these data with a study of how flight initiation distance (FID) changed between the six sites, as an indicator of the level of tolerance that ibex exhibit to increased anthropogenic presence. We found that as anthropogenic presence increas...
Insectes Sociaux, 2017
show that a single queen inhabits the great majority of burrows. Some burrows, however, are occup... more show that a single queen inhabits the great majority of burrows. Some burrows, however, are occupied by two or three queens, and we even found a burrow that contained eight queens together. The prevalence of these multi-queen associations depends on the terrain. About 5% of the newly dug burrows in open areas (terra rossa over hard limestone, with Mediterranean scrub) contain more than a single queen, and this proportion can reach 20% in paved areas. These observations led us to conduct Abstract After landing at the end of their nuptial flight, young queens of the harvester ant Messor semirufus search for a suitable nesting site and dig a burrow. After 3 months in the burrow, they start laying eggs, and nurse their first brood of workers alone. Field observations indicate that a few newly dug burrows contain more than one queen. Laboratory experiments were conducted in order to discover why these young queens' associations form. We found that groups do not exhibit any productive advantage over singlefounding queens, either with respect to progeny number, or with respect to the time until the first eggs are laid. Groups have a slower rate of nest digging than single queens, and mortality rate is considerably higher for queens in groups than for single queens. From the initiation of the group, queen interactions involve aggression and a behavioral hierarchy, with a prior-residence advantage. The tendency to form groups is stronger if queens density is greater and if digging conditions, characterized by soil hardness, are less favorable. We conclude that foundress associations in M. semirufus are in fact the result of nest invasions in an attempt to displace the resident queen. These are motivated by the high cost of the search for a suitable nesting site and of the digging of the nest.
Disease associations and disequilibrium mapping
Progress in clinical and biological research, 1989
Affected sib pair IBS methods: detection of linkage and genetic models
Progress in clinical and biological research, 1989
Insectes Sociaux, 2016
Field observations on the behavior of young queens of the harvester ant Messor semirufus, reveal ... more Field observations on the behavior of young queens of the harvester ant Messor semirufus, reveal a considerable variance among individuals in the time span between landing after nuptial flight, and the start of nest digging. During that interval, which can last from a few minutes to almost 2 h, the queens wander around while being exposed to many dangers, especially to the risk of predation. Furthermore, queens were observed digging in places where other queens have just passed through and declined to dig. We hypothesized that M. semirufus queens are performing a sequential sampling of the environment, to deduce its quality distribution, before making the decision to dig. To test this hypothesis, we conducted laboratory experiments to examine the influence of two factors, soil hardness and queen density, on digging decisions. The results indicate that these factors indeed affect the walking and searching time until digging. Furthermore, it turns out that the young queens are able to perceive and react to changes, either an improvement or a deterioration, in soil hardness and in queen density: their digging decision is stimulated by an improvement, and impeded by a deterioration in these factors, relative to initial condition.
Theoretical and Applied Genetics, Feb 1, 1993
As compared to classical, fixed sample size techniques, simulation studies showed that a proposed... more As compared to classical, fixed sample size techniques, simulation studies showed that a proposed sequential sampling procedure can provide a substantial decrease (up to 50~, in some cases) in the mean sample size required for the detection of linkage between marker loci and quantitative trait loci. Sequential sampling with truncation set at the required sample size for the non-sequential test, produced a modest further decrease in mean sample size, accompanied by a modest increase in error probabilities. Sequential sampling with observations taken in groups produced a noticeable increase in mean sample size, with a considerable decrease in error probabilities, as compared to straightforward sequential sampling. It is concluded that sequential sampling has a particularly useful application to experiments aimed at investigating the genetics of differences between lines or strains that differ in some single outstanding trait.
Natural mortality of the tobacco whitefly (Bemisia tabaci) in Israel cotton fields
Selfish cooperation in social roles: the vigilance game in continuous time
Springer eBooks, 1990
Social interactions in nature often involve conflict to a certain extent. Game theory can sometim... more Social interactions in nature often involve conflict to a certain extent. Game theory can sometimes provide us with insight and tools to improve our understanding of how natural selection has resolved such conflicts. Undoubtedly, the major conceptual tool in this field is the concept of evolutionarily stable strategies (ESS), which was introduced by Maynard Smith and Price (1973). A strategy, in an evolutionary context, is one of a set of possible alternative behavioural programmes that an individual in a population can adopt. It is usually assumed that these are genetically determined. An ESS is a strategy which, when adopted by a large enough fraction of the population, cannot be invaded by any alternative rare (‘mutant’) strategy. A rare ESS strategy can invade a non-ESS population.
Journal of Forensic Sciences, Jul 1, 1999
This case report demonstrates a rape case, where no semen, hair, or fingerprints were left by the... more This case report demonstrates a rape case, where no semen, hair, or fingerprints were left by the perpetrator at the crime scene, but rather uncharacteristic biological and physical evidence in the form of a lollipop and a pair of glasses. Three separate forensic laboratories collaborated using conventional forensic methods of PCR DNA typing, photography, and toolmark comparisons to provide investigators with scientific evidence which in turn was instrumental in bringing a violent criminal to justice. The importance of evaluating each item of evidence and realizing its forensic value is stressed in this case report.
Effect of supplemental feeding on nesting success in the Lesser Kestrel (Falco naumanni)
RePEc: Research Papers in Economics, 2018
<jats:p>The effect of food supplement to Lesser Kestrel (<jats:italic>Falco naumanni&... more <jats:p>The effect of food supplement to Lesser Kestrel (<jats:italic>Falco naumanni</jats:italic>) nests during the nestling period (from hatching to fledging) was studied in two nesting colonies in Israel – Alona and Jerusalem. Our hypothesis, based on diminishing returns considerations, was that food supplement will have a greater effect on fledgling success in the food-limited, urban colony of Jerusalem, than in the rural colony of Alona. Indeed, food supplement had a significantly positive effect on breeding success in both colonies. However, and contrary to our prediction, the decrease in chick mortality between supplemented and control nests in Jerusalem was not larger than in Alona (actually it was numerically smaller, albeit not significantly so). This implies either that additional factors, possibly urbanization associated, other than food limitation, might be responsible for the difference in nesting success of Lesser Kestrels between Alona and Jerusalem, and/or that the amount or the nutritional quality of the additional food provided to supplemented nests (three mice per chick per week), was not enough.</jats:p>
The Three Brothers' Problem: Kin Selection
The theory of kin selection was introduced by Hamilton (1963, 1964) and developed further by many... more The theory of kin selection was introduced by Hamilton (1963, 1964) and developed further by many others in terms of help directed from one relative (the donor) toward another (the recipient). In this paper, as well as its companion (Eshel and Motro 1988), we deal with the more complex (though quite common) situation in which an individual needs help, and this help can be provided (with some risk to the donor) by each of several relatives. In such a situation, even if Hamilton's condition for altruism between two relatives is satisfied, it is advantageous to stand by and wait for another relative to take the risk and help the relative in need. It is true, though, that if all helpers are passive, Hamilton's argument again holds, and any potential helper can increase its own inclusive fitness by exclusively taking the risk and saving the relative in need. However, this entails an even greater increase in the inclusive fitness of the other relatives that decided not to offer their help. The analysis of situations involving more than one potential helper carried out in the preceding paper (Eshel and Motro 1988) and in this paper reveals that if Hamilton's condition for one-to-one altruism does not hold, full selfishness is the only evolutionarily stable strategy (ESS) independent of the number of helpers. If, however, Hamilton's condition is satisfied, the ESS in the multiple-help cases is usually a mixed strategy of altruism and selfishness, characterized by a positive probability of providing the needed help. In the preceding paper we analyzed situations in which immediate help is needed. In such cases, each potential helper has to decide instantaneously whether or not to offer its help, without knowing what the other potential helpers are doing. Here we discuss the case of delayed help. Each potential helper can wait in the hope that another relative will take the risk and help the individual in need; yet if they all hesitate too long, it might be too late for the relative in distress. We first present an ESS model of delayed help, based on arguments of the maximization of inclusive fitness. We then add a simple genetic model, whose results coincide (at least for the case studied) with those obtained by the ESS
Journal of Theoretical Biology, Jun 1, 2004
The parental investment conflict considers the question of how much each sex should invest in eac... more The parental investment conflict considers the question of how much each sex should invest in each brood, thereby characterizing different animal groups. Each such group usually adopts a certain parental care pattern: female-care only, male-care only, biparental care, or even no parental care at all. The differences in care patterns are usually explained by the different costs and benefits arising from caring for the offspring in each animal group. This paper proposes a game-theoretical model to the parental investment conflict based on the parental behavior in Cichlid fish. Cichlid fish exhibit different parental care patterns, allowing the examination of the factors which determine the particular behavior in each mating. We present a continuous time, two-stage, asymmetric game, with two types of players: male and female. According to the model's results, three parental care patterns: male-only care, female-only care and biparental care, are possible Evolutionarily Stable Strategies. Fixation depends on the investment costs and benefits, and on the initial conditions of the game. These results may explain the different parental care patterns observed in different animal groups as well as in Cichlid fish.
bioRxiv (Cold Spring Harbor Laboratory), May 25, 2020
The circadian and endocrine systems influence many physiological processes in animals, but little... more The circadian and endocrine systems influence many physiological processes in animals, but little is known on the ways they interact in insects. We tested the hypothesis that juvenile hormone (JH) influences circadian rhythms in the social bumble bee Bombus terrestris. JH is the major gonadotropin in this species coordinating processes such as vitellogenesis, oogenesis, wax production, and behaviors associated with reproduction. It is unknown however, whether it also influences circadian processes. We topically treated newly-emerged bees with the allatoxin Precocene-I (P-I) to reduce circulating JH titers and applied the natural JH (JH-III) for replacement therapy. We repeated this experiment in three trials, each with bees from different source colonies. Measurements of ovarian activity suggest that our JH manipulations were effective; bees treated with P-I had inactive ovaries, and this effect was fully recovered by subsequent JH treatment. We found that JH augments the strength of circadian rhythms and the pace of rhythm development in individually isolated newly emerged worker bees. JH manipulation did not affect the free-running circadian period, overall level of locomotor activity, sleep amount, or sleep structure. Given that acute manipulation at an early age produced relatively long-lasting effects, we propose that JH effects on circadian rhythms are mostly organizational, accelerating the development or integration of the circadian system.
Nest-site fidelity in Lesser Kestrels: a case of Win–Stay/Lose–Shift?
Israel Journal of Ecology & Evolution, Nov 6, 2019
We studied Lesser Kestrels’ (Falco naumanni) conditional nest-site fidelity, i.e., fidelity that ... more We studied Lesser Kestrels’ (Falco naumanni) conditional nest-site fidelity, i.e., fidelity that depends on the outcome of the previous nesting attempt in that site. In particular, we were interested in examining whether individual kestrels practice a Win–Stay/Lose–Shift (WSLS) strategy towards their nest-sites; that is, does the tendency to use the same nest-site increase following a successful nesting season, but decrease following a failure. For that purpose, we documented the use of nest-sites by Lesser Kestrels and the breeding success in these sites during 1998–2003 in the city of Jerusalem (Israel). We found that while Lesser Kestrels do not practice WSLS strategy towards their nest-site, the males (but not the females) do so towards their sub-colony – they tend to stay in the same sub-colony if their nesting was successful, whereas they tend to migrate to a different sub-colony after failure. A possible explanation to this sexual difference in WSLS behavior can arise from the fact that changing a sub-colony entails a change of hunting area. The male, being the main food provider in the Lesser Kestrel, may be more sensitive to this opportunity.
Molecular analysis separates the Atlantic population of Montagu's stellate barnacle into two cryptic species
Zoologica Scripta
Brewed in the African pot: the phylogeography of the toothed barnacle Chthamalus dentatus (Chthamaloidea: Chthamalidae)
Marine Biology Research
Insects
During recent decades, bumble bees (Bombus terrestris) have continuously expanded their range in ... more During recent decades, bumble bees (Bombus terrestris) have continuously expanded their range in the Mediterranean climate regions of Israel. To assess their potential effects on local bee communities, we monitored their diurnal and seasonal activity patterns, as well as those of native bee species in the Judean Hills. We found that all bee species tend to visit pollen-providing flowers at earlier times compared to nectar-providing flowers. Bumble bees and honey bees start foraging at earlier times and colder temperatures compared to other species of bees. This means that the two species of commercially managed social bees are potentially depleting much of the pollen, which is typically non-replenished, before most local species arrive to gather it. Taking into consideration the long activity season of bumble bees in the Judean hills, their ability to forage at the low temperatures of the early morning, and their capacity to collect pollen at early hours in the dry Mediterranean cli...
The impact of Acacia saligna and the loss of mobile dunes on rodent populations: a case study in the Ashdod-Nizzanim sands in Israel
Israel Journal of Plant Sciences, 2019
The Mediterranean coastal dune habitat of Israel is diminishing rapidly, mostly due to massive ur... more The Mediterranean coastal dune habitat of Israel is diminishing rapidly, mostly due to massive urbanization, changes in habitat characteristics caused by dune stabilization and the presence of Acacia saligna, an invasive species brought to Israel for the purpose of dune stabilization. In this study we document the effect of sand stabilization on the composition of small mammal communities in the Ashdod-Nizzanim sands, Israel. We analyzed differences in species diversity and abundance for species of rodents in four types of habitat: unstable (mobile) sand dune, semi-stabilized dune, inter-dune depression and a plot of the invasive Acacia saligna. Rodent communities were found to undergo gradual changes concurrently with the stabilization of the sands. The mobile dune was the only habitat in which the strict psammophiles Jaculus jaculus and Gerbillus pyramidum were captured in abundance. No species commensal with human were captured neither in the mobile nor in the semi-stabilized dun...
Mammal Research, 2019
A trapping study was conducted to compare the efficacy of 11 different small mammal traps-seven l... more A trapping study was conducted to compare the efficacy of 11 different small mammal traps-seven live-traps and four lethaltraps-in capturing pest rodents in agricultural fields and orchards. The 9-year study was carried out in various regions in Israel, and comprised of 648 trap-sets, totalling over 32,000 trap-nights. Mice comprised the great majority (over 85%) of captures, with Tristram's jirds in the second place (about 8%). Among the traps, the Victor Mouse snap-trap displayed the greatest capturing rate (10.05%), followed by the Sherman live-trap (8.88%) and the Ugglan live-trap (6.28%). Pairwise comparisons were performed only between the four most abundant traps-Victor Mouse, Box, Victor Rat, and Sherman. For mice, the most attractive trap was the Victor Mouse, second in attractiveness was the Sherman, third was the Box live-trap, and the least of the four was the Victor Rat snap-trap. For the larger jirds, the attractiveness hierarchy was reversed, with Victor Mouse being the least attractive. These results shed light on rodent traps and rodent trappability in various agricultural environments and with regard to target species. A careful choice of trap types should be exercised to best address mission goals.
Israel Journal of Ecology and Evolution, 2017
We studied the use of nest-sites by Griffon Vultures (Gyps fulvus) and the breeding success in th... more We studied the use of nest-sites by Griffon Vultures (Gyps fulvus) and the breeding success in these sites during 1998–2002 in Gamla Nature Reserve (Israel). Nest-sites in which a breeding attempt succeeded in fledging a young, were more likely to be occupied by nesting vultures in the following breeding season, than nest-sites that experienced a failure. This suggests that Griffon Vultures in Gamla used a Win–Stay/Lose–Shift strategy regarding nest-site fidelity.
Animal Conservation, 2018
Increased fragmentation and easier access to natural areas (e.g. ecotourism) is bringing man in c... more Increased fragmentation and easier access to natural areas (e.g. ecotourism) is bringing man in closer contact to wild populations. Such encounters, even when they don't pose a direct threat to wildlife, may induce behavioral changes in animals that in the long run may have negative fitness consequences. We studied changes to the vigilance/group‐size effect in Nubian ibex Capra nubiana in response to increased non‐threatening anthropogenic disturbance in six sites, subject to different levels of ecotourism. In each site we regressed the average time ibex individuals devoted to vigilance on the size of the group they were with. We then compared the slopes and intercepts of the vigilance/group‐size function between the six sites. We complimented these data with a study of how flight initiation distance (FID) changed between the six sites, as an indicator of the level of tolerance that ibex exhibit to increased anthropogenic presence. We found that as anthropogenic presence increas...
Insectes Sociaux, 2017
show that a single queen inhabits the great majority of burrows. Some burrows, however, are occup... more show that a single queen inhabits the great majority of burrows. Some burrows, however, are occupied by two or three queens, and we even found a burrow that contained eight queens together. The prevalence of these multi-queen associations depends on the terrain. About 5% of the newly dug burrows in open areas (terra rossa over hard limestone, with Mediterranean scrub) contain more than a single queen, and this proportion can reach 20% in paved areas. These observations led us to conduct Abstract After landing at the end of their nuptial flight, young queens of the harvester ant Messor semirufus search for a suitable nesting site and dig a burrow. After 3 months in the burrow, they start laying eggs, and nurse their first brood of workers alone. Field observations indicate that a few newly dug burrows contain more than one queen. Laboratory experiments were conducted in order to discover why these young queens' associations form. We found that groups do not exhibit any productive advantage over singlefounding queens, either with respect to progeny number, or with respect to the time until the first eggs are laid. Groups have a slower rate of nest digging than single queens, and mortality rate is considerably higher for queens in groups than for single queens. From the initiation of the group, queen interactions involve aggression and a behavioral hierarchy, with a prior-residence advantage. The tendency to form groups is stronger if queens density is greater and if digging conditions, characterized by soil hardness, are less favorable. We conclude that foundress associations in M. semirufus are in fact the result of nest invasions in an attempt to displace the resident queen. These are motivated by the high cost of the search for a suitable nesting site and of the digging of the nest.
Disease associations and disequilibrium mapping
Progress in clinical and biological research, 1989
Affected sib pair IBS methods: detection of linkage and genetic models
Progress in clinical and biological research, 1989
Insectes Sociaux, 2016
Field observations on the behavior of young queens of the harvester ant Messor semirufus, reveal ... more Field observations on the behavior of young queens of the harvester ant Messor semirufus, reveal a considerable variance among individuals in the time span between landing after nuptial flight, and the start of nest digging. During that interval, which can last from a few minutes to almost 2 h, the queens wander around while being exposed to many dangers, especially to the risk of predation. Furthermore, queens were observed digging in places where other queens have just passed through and declined to dig. We hypothesized that M. semirufus queens are performing a sequential sampling of the environment, to deduce its quality distribution, before making the decision to dig. To test this hypothesis, we conducted laboratory experiments to examine the influence of two factors, soil hardness and queen density, on digging decisions. The results indicate that these factors indeed affect the walking and searching time until digging. Furthermore, it turns out that the young queens are able to perceive and react to changes, either an improvement or a deterioration, in soil hardness and in queen density: their digging decision is stimulated by an improvement, and impeded by a deterioration in these factors, relative to initial condition.